1. Field of the Invention
The present invention relates to a continuously adjustable rescue strut intended to be used as a temporary strut for maintain two objects in a spaced position with respect to each other. More particularly, it relates to a strut of continuously adjustable length intended for use by emergency or rescue personnel to support portions of collapsed building or other structures, such as the wall or a collapsing excavation, in a spaced relationship with respect to each other, so as to permit rescue operations to proceed without the danger of the supported portions moving into a closer position with respect to each other.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Adjustable length rescue support or strut systems have been provided in the past for use by emergency and rescue personnel for maintaining structures in a spaced relationship with respect to each other. Generally such strut systems are constructed with an inner member being telescopically received in an outer member. The opposite ends of the inner and outer members are each provided with a base suitable for engaging the surface to be supported. A mechanism is provided to maintain the inner and outer members in a desired telescopic relationship with each other, whereby the length of the strut is such that each of the bases engages the surface to be supported. In an elementary form, struts have been formed by inner and outer strut members, each of which is provided with a series of holes perpendicular to and spaced apart along the major axis of each member. The inner and outer members are extended with respect to each other to the desired overall length, and then adjusted with respect to each other to permit a pin to be place in aligned holes in the inner and outer members. A strut of this type is not preferred by rescue personnel, wherein a person must not only place the strut between the surfaces to be supported, but must also adjust the strut to the desired length and then place a pin in aligned holes in the inner and outer members. Thus, the rescue person is exposed to possible shifting of the surfaces to be supported both before and after the strut is in place.
The assignee of the subject application has provided a variety of rescue support or strut systems which are preferred to that just described. The strut systems provided by the assignee of the subject application are designed to be extendable to a desired length, either manually or by remote operation. To provide for remote operation, the inner and outer members are designed to form a cylinder to which pneumatic pressure may be applied to extend the members with respect to each other.
In one of the strut systems provided by the assignee of the subject application, the inner member is provided with a plurality of spaced circumferential notches which receive ball bearings supported in a collar mechanism attached to the outer member. The collar mechanism is movable with respect to the outer member between two positions. With the collar in a first position the inner member is freely movable with respect to the outer member. With the collar in the second position and a compressive or no force applied to the free ends of the strut, the ball bearings are engaged in the notches in the inner member to lock the inner and outer members in position with respect to each other. However, if a force is applied to extend the outer and inner members with respect to each other, the ball bearing are disengaged from the notches in the inner member and the outer and inner members may be extended with respect to each other. The collar is operable between the two positions, either manual or by pneumatic pressure. If a remote handling device is used to place the strut between the surfaces to be supported, the extension and securing in position of the inner and outer members with respect to each other can be accomplished by pneumatic pressure supply through hoses, such that a rescue person need not be endangered by manually positioning the strut system. A limitation on this strut system is that the length is not continuously adjustable. Rather, the length is incrementally adjustable, depending on the spacing of the grooves in the inner member. In a strut system provided by the assignee of this application, the increment is 0.40 inches.
In certain situations, it is most desirable that the strut be adjustable to the exact spacing of the surfaces to be supported, such that even a slight shifting of the surfaces toward each other is not possible with the strut in place. The assignee of this application has provided a strut system which is continuously adjustable in length, and which as in the case of the previously described strut system may be remotely extend by pneumatic pressure. Again, the inner and outer members are designed to form a cylinder to which pneumatic pressure may be applied to extend the members with respect to each other. The outer surface of the inner member is provided with an Acme thread, which is engaged by an Acme threaded nut. After the strut is extended to the desired length, the acme nut is rotated to engage the end of the outer member. While this strut system may be continuously adjusted in length, such that it can be remotely adjusted to the exact spacing of the surfaces to be supported, it does require the manual rotation of the acme nut to secure or lock the inner and outer members in the desired position with respect to each other. Thus, prior to this invention, a strut system providing both continuous extension and locking by remote control has not been available.
It is an object of this invention to provide a support or strut system which is continuously adjustable in length, for use by emergency and rescue personnel for maintaining structures in a spaced relationship with respect to each other. It is a further object of this invention to provide a support or strut system which is continuously adjustable length and which may be remotely extended in length and locked at the desired length, and remotely unlocked to permit retraction or shortening of the strut.
In accordance with this invention a strut system continuously adjustable in length, and providing both remote extension of the length and locking at the desired length, and remote unlocking to permit retraction or shortening of the strut is provided.